I think I have 2 seperate problems. First when I have just my vent on in my truck its as cold as my a/c. I'm guessing this isn't right. Also my e-fan runs constantly. Would my ac being constantly on cause this? And what would cause tje ac to be on constantly.

Also went for a 200 mile drive last weekend. After about 45 minutes on the highway my heat gauge was about 3/4 of the way up so I turn the heat on and roll down the windows and itd get better. Turn the vent on and about 10-15 minutes later it'd be back to 3/4 of the way. Is this related somehow to my e-fan being on all the time or just a sticky thermostat? I drive 20 miles a day to work on the highway and the gauge never goes over half way. Thats why I'm not sure what it is.

 

a/c might be low on 134a(refrigerant) might be the reason. just a guess.

if your antifreeze isn't low. i would try a different t-stat. if your e-fan run runs nonstop, i would like to think that the water temp would be lower do to the fact of constant air being pulled across the coils.

 

Low refrigerant won't cause the a/c to run. In fact, it'll shut down the compressor. It sounds more like a control problem. Are you sure you have it in just the vent position?
The PCM will call for the fan if the a/c is on so these two might be related.

The e-fan running won't cause your truck to run hot. Especially at highway speeds, the fan isn't really necessary. Earlier years didn't even have them. Have you checked the coolant level? When's the last time you serviced it? How's the belt?

You might want to have the radiator "sniffed" with an exhaust gas detector. It may be a head gasket failing that's causing it to get hot.

 

Too high of pressure will cause the AC to run hotter thus the air is hotter to cool the Rad which will raise temps.. but it running while the Vent is on.. when AC should not be running sounds like a problem.

 

I'm positive that the control is in the vent position and it blows just as cold as the ac. If the ac is constantly running this would explain why the e-fan is constantly on.

The running hot I'm not so sure on. If I drive 20 miles a night to get to work I don't have a problem but if I drive an hour straight it gets hot. Yes there's coolant in the overflow tank and in the tube between that and the radiator were the cap is. I don't know if the coolant has ever been serviced. I just bought the truck in May and am almost at 58,000 miles. I'm going to look in the owners manual to see when it suggest a coolant flush be done.

 

Try this unplug both A/C sensors see if that helps thats a start to understanding if that is what is going on

Disconnecting them should shut the A/C off

 

unplugged both a/c sensors e-fan still came on right away. I haven't drove the truck at all since last night. I started it once this morning after changing my oil and about an hour and a half later after unplugging the sensors so the truck isn't warm at all. Took a pic just to make sure I unplugged the right stuff. Now I'm thinking maybe the fan relay?

 

Looks like you did ok just make sure the wires dont get sucked into the belt and get chewed up.

Does it still feel like the A/C is on if so thats imposable and not what is going on.

If it shows the water is still cold all the time Im thinking sensor.

If the fan is on all the time still thats not right that is something 00DakDan is good at.

There should be two sensors for the A/C one is on your drier receiver the round thing that’s attached to the compressor by a large diameter hose



Or look like this

 

I'm going to be taking about a half hour drive later so I'll leave the plugs unplugged tape them out of the way and see what happens.

 

The plug you pulled is for the a/c clutch, that's it. It won't stop the fan. The PCM controls the fan relay. Something is telling it to run.

Pull the connectors 98 shows you. That'll turn off the a/c and the pcm will know about it. Your way, the pcm is still trying to engage the clutch.